Patch "tracing: Fix parsing of globs with a wildcard at the beginning" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

tracing: Fix parsing of globs with a wildcard at the beginning

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
tracing-fix-parsing-of-globs-with-a-wildcard-at-the-beginning.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: "Steven Rostedt (VMware)" <[email protected]>
Date: Mon, 5 Feb 2018 22:18:11 -0500
Subject: tracing: Fix parsing of globs with a wildcard at the beginning

From: Steven Rostedt (VMware) <[email protected]>

commit 07234021410bbc27b7c86c18de98616c29fbe667 upstream.

Al Viro reported:

For substring - sure, but what about something like "*a*b" and "a*b"? AFAICS, filter_parse_regex() ends up with identical results in both cases - MATCH_GLOB and *search = "a*b". And no way for the caller to tell one from another.

Testing this with the following:

 # cd /sys/kernel/tracing
 # echo '*raw*lock' > set_ftrace_filter
 bash: echo: write error: Invalid argument

With this patch:

 # echo '*raw*lock' > set_ftrace_filter
 # cat set_ftrace_filter
_raw_read_trylock
_raw_write_trylock
_raw_read_unlock
_raw_spin_unlock
_raw_write_unlock
_raw_spin_trylock
_raw_spin_lock
_raw_write_lock
_raw_read_lock

Al recommended not setting the search buffer to skip the first '*' unless we know we are not using MATCH_GLOB. This implements his suggested logic.

---
 kernel/trace/trace_events_filter.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

@@ -400,7 +400,6 @@ enum regex_type filter_parse_regex(char
 	for (i = 0; i < len; i++) {
 		if (buff[i] == '*') {
 			if (!i) {
-				*search = buff + 1;
 				type = MATCH_END_ONLY;
 			} else if (i == len - 1) {
 				if (type == MATCH_END_ONLY)

@@ -410,14 +409,14 @@ enum regex_type filter_parse_regex(char
 				buff[i] = 0;
 				break;
 			} else {	/* pattern continues, use full glob */
-				type = MATCH_GLOB;
-				break;
+				return MATCH_GLOB;
 			}
 		} else if (strchr("[?\\", buff[i])) {
-			type = MATCH_GLOB;
-			break;
+			return MATCH_GLOB;
 		}
 	}
+	if (buff[0] == '*')
+		*search = buff + 1;
 
 	return type;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/tracing-prevent-profile_all_branches-when-fortify_source-y.patch queue-4.14/tracing-fix-parsing-of-globs-with-a-wildcard-at-the-beginning.patch